Mobile subscribers register with a network as a way of informing the network of the presence of a mobile subscriber in different communication areas within a network. When a mobile subscriber registers with the network, the mobile subscriber communicates with one or more base stations, which are each responsible for communications within a predesignated area, often referred to as a cell. A particular base station will generally only be able to communicate with a mobile subscriber, if the mobile subscriber is proximate to the area, that the base station is associated with. Consequently, an ability to communicate with a base station will often help identify the proximate location of a mobile subscriber, relative to a network.
By identifying the proximate location of a mobile subscriber, and/or identifying the base stations, which are capable of communicating with a mobile subscriber, when a call or message is received for a mobile subscriber, the network is better able to establish the necessary supporting communication links. The on-going performance of registrations at various time intervals, which are often associated with a change of power state or movement of a mobile subscriber between different communication areas, allows the network to maintain current information relative to a particular mobile subscriber.
Generally, a mobile subscriber will maintain a single registration, which is consistent with its present location relative to one or more communication areas, such as a packet zone ID. As the mobile subscriber moves into an area corresponding to a different packet zone ID, the mobile subscriber will register with the new area, and as part of the process will terminate or tear down any prior registrations. When a mobile subscriber is proximate a border region between two different areas, this can result in frequent registrations by the mobile subscriber, especially if the mobile subscriber moves back and forth across the border.
Frequent registrations can sometimes result in a couple of negative consequences, insofaras that each time that a registration occurs, a mobile subscriber may be momentarily unavailable to receive incoming messages and/or calls. Furthermore, the period of unavailability, while the mobile subscriber is registering with a new area, can sometimes last several seconds. This can sometimes constitute an unacceptable delay, for example, where a user may be engaged in a push-to-talk call, in which a more immediate response is expected. In addition to the mobile subscriber being unavailable to receive calls and/or messages, the additional communication activities associated with the registration process may also have an impact on battery life. Consequently, it would be beneficial to reduce the need for subsequent registrations.
In some systems, it is possible to maintain multiple registrations, but the default is to maintain only a single registration. In order to support the maintenance of multiple registrations, additional signaling and/or specific instructions is generally required, above and beyond the signaling associated with regular communications, which also generally must be repeated in connection with each subsequent registration.
The present inventors have recognized that in at least some instances, it may be beneficial to be able to retain earlier registration information, that could be used upon subsequent re-entry into an area in which the mobile subscriber was previously located and with which the mobile subscriber had previously been registered with. Furthermore, it would be beneficial to retain the earlier registration information without requiring additional messages and/or signaling associated with each registration.